Neonatal outcomes after the implantation of human embryos vitrified using a closed-system device

Comparison of the effect of two commercialized vitrification carriers on pregnancy outcomes in freeze-thaw cycles

OBJECTIVE

This study aimed to compare the effects of two brands of commercial vitrification carriers on pregnancy outcomes in freeze-thaw cycles.

METHODS

We included 4871 patients who underwent a "freeze all" strategy using the commercial carriers J.Y. straw and OYASHIPS straw in the Reproductive Center of the First Hospital of Jilin University. The pregnancy outcomes of cleavage-stage embryos and blastocysts were studied separately. Detailed data and the safety of children born from mothers with the two types of carriers were also compared.

RESULTS

Patients who used J.Y. straw had similar clinical pregnancy and live birth rates with one and two cleavage-stage embryo transplantation to those who used OYASHIPS straw. In patients who had blastocyst transplantation, the clinical pregnancy rate of one blastocyst transplanted in those who used OYASHIPS straw was significantly higher than that in those who used J.Y. straw (57.85% vs 47.09%). Among children born from mothers who used J.Y. straw, the congenital disability rate was significantly higher than that in those with OYASHIPS straw.

CONCLUSION

The OYASHIPS straw carrier is cheap and can achieve clinical pregnancy and live birth outcomes comparable to those of J.Y. straw. Therefore, OYASHIPS straw is a good alternative option.

Open versus closed vitrification system of human oocytes and embryos: a systematic review and meta-analysis of embryologic and clinical outcomes

BACKGROUND

The objective of this study was to carry out a systematic review and meta-analysis of embryologic and clinical outcomes following open versus closed vitrification of human oocytes and embryos.

METHODS

An electronic literature search was conducted in main electronic databases up to June 30, 2018 using the following key terms: 'oocyte', 'embryo', 'blastocyst', 'vitrification', 'cryopreservation', 'device', 'survival rate', 'pregnancy rate', etc. A meta-analysis was performed using a random effect model to estimate the value of risk ratios (RRs) and 95% confidence interval (CI). Subgroup analyses and sensitivity analyses were carried out to further confirm the results.

RESULTS

Twelve (Eight prospective and four retrospective) studies comparing open versus closed vitrification of human oocytes or embryos were included. For prospective studies on oocytes, no evidence for a significant difference in cryosurvival rate (RR = 0.91, 95% CI: 0.80-1.03, P = 0.14; n = 2048) or clinical pregnancy rate (RR = 1.29, 95% CI: 0.80-2.06, P = 0.30; n = 150) was observed. Additionally, there were no significant differences between the two methods concerning secondary endpoints included positive βHCG rate, implantation rate, miscarriage rate, ongoing pregnancy rate, live birth rate, cancellation rate, babies born per transferred blastocysts, or multiple birth rate (P > 0.05). The results of the retrospective studies were similar as the prospective studies.

CONCLUSIONS

It is still impossible to conclude that closed vitrification system could be a substitution for open system in human oocyte and embryo cryopreservation based on current evidence. Therefore, more well-designed prospective studies addressing these issues are still warranted.

Oral administration of l-carnitine improves the clinical outcome of fertility in patients with IVF treatment

Age-dependent decline of mitochondrial function has been proposed to be a main cause of decline of embryo quality. Then, l-carnitine plays important roles in reducing the membranous toxicity of free-fatty acids by forming acyl-carnitine and promoting β-oxidation, preventing cell damage. Recent research revealed that l-carnitine played important roles in vitro in oocyte growth, oocyte maturation and embryo development. However, such beneficial effects of l-carnitine in vivo have yet to be verified. The effect of oral l-carnitine supplementation on embryo quality and implantation potential was examined. A total of 214 patients were included in this study. They all previously received in vitro fertilization-embryo transfer (IVF-ET) and failed to conceive. Then they were administered l-carnitine for 82 days on average and underwent IVF-ET again. There were no significant differences in the total number of retrieved oocytes, and their maturation and fertilization rates between before and after l-carnitine administration. The quality of embryos on Days 3 and 5 after insemination was improved following l-carnitine administration (p < .05) in cycles after l-carnitine administration compared with previous cycles. Healthy neonates were born after IVF-ET following l-carnitine administration. Our data suggested that oral administration of l-carnitine to fertility patients improved the developmental competence of their oocytes after insemination.

Comparison of two closed carriers for vitrification of human blastocysts in a donor program

The survival of human blastocysts to vitrification with two different carriers is compared. Both vitrification carriers used in this study are in the category of closed carriers, as they completely isolate the samples from direct contact with liquid nitrogen or its vapours during cooling and storage, until warming. This characteristic is appealing because it reduces or eliminates the theoretical risk of cross-contamination during that period of time. The two closed vitrification systems used present very different design and features: in the High Security Vitrification device, the carrier straw containing the embryos is encapsulated inside an external straw before plunging in liquid nitrogen, resulting in thermal insulation during cooling. On the other hand, in the SafeSpeed carrier embryos are loaded in a thin-walled, narrow capillary designed to maximize the thermal transference. Both closed carriers achieved comparable outcomes in terms of survival of blastocysts to the vitrification process, with 97.5% vs. 96.1% survival with HSV and SafeSpeed, respectively. In conclusion, the cooling and warming rates at which these carriers operate, in combination with the cytosolic solute concentration in the cells of the cryopreserved blastocysts attained after a cryoprotectant-loading protocol, result in successful vitrification of human blastocysts for human assisted reproduction.

Closed versus open vitrification for human blastocyst cryopreservation: A meta-analysis

Closed vitrification can minimize the risk of microbiological transmission through liquid nitrogen during the cooling, storage, and warming procedures. As cooling rates may reduce when closed vitrification is applied, clinical outcomes should be compared between closed and open vitrification in order to justify the use of closed vitrification. This study was conducted to investigate the differences in survival, implantation, clinical pregnancy, and live birth rates between closed and open vitrification for human blastocyst cryopreservation. This systematic review and meta-analysis included 7 studies that reported survival, implantation, clinical pregnancy, or live birth rates following closed or open vitrification. There were no statistically significant differences in survival rates (risk ratio [RR]: 1.00, 95% confidence interval [CI]: 0.98-1.02), implantation rates (RR: 1.02, 95% CI: 0.93-1.11), clinical pregnancy rates (RR: 0.99, 95% CI: 0.89-1.10), and live birth rates (RR: 0.77, 95% CI: 0.58-1.03) between closed and open vitrification. Although there was no statistical significance, the tendency of lower live birth rates with closed vitrification than with open vitrification could be clearly identified. Therefore, it is not yet possible to conclude that closed vitrification clearly provides an aseptic alternative to open vitrification in human blastocyst cryopreservation.

Epigenetic Influences During the Periconception Period and Assisted Reproduction

The periconception period starts 6 months before conception and lasts until the tenth week of gestation. In this chapter, we will focus on epigenetic modifications to DNA and gene expression within this period and during assisted reproduction. There are two critical times during the periconception window when significant epigenetic 'reprogramming' occur: one during gametogenesis and another during the pre-implantation embryonic stage. Furthermore, assisted conception treatments, laboratory protocols and culture media can affect the embryo development and birth weights in laboratory animals. There is, however, an ongoing debate as to whether epigenetic changes in humans, causing embryo mal-development, placenta dysfunction and birth defects, result from assisted reproductive technologies or are consequences of pre-existing medical and/or genetic conditions in the parents. The periconception period starts from ovarian folliculogenesis, through resumption of oogenesis, fertilisation, peri-implantation embryo development, embryogenesis until the end of organogenesis. In men, it is the period from spermatogenesis to epididymal sperm storage and fertilisation. Gametes and developing embryos are sensitive to environmental factors during this period, and epigenetic modifications can occur in response to adverse lifestyles and environmental factors. We now know that lifestyle factors such as advanced parentage age, obesity or undernutrition, smoking, excessive alcohol and caffeine intake and recreational drugs used during gamete production and embryogenesis could induce epigenetic alterations, which could impact adversely on pregnancy outcomes and health of the offspring. Furthermore, these can also result in a permanent and irreversible effect in a dose-dependent manner, which can be passed on to the future generations.

Closed vitrification of human oocytes and blastocysts: outcomes from a series of clinical cases

PURPOSE

High survival rates and clinical outcomes similar to those from fresh oocytes and blastocysts have been observed with open oocyte vitrification systems. It has been suggested that the extremely fast cooling rates that are only achieved with open systems are necessary for human oocyte and blastocyst vitrification. However, there is a potential risk of introducing contamination with open systems. The aim of this study was to assess whether similar survival and subsequent implantation rates could be achieved using a closed vitrification system for human oocytes and blastocysts.

METHODS

Initially, donated immature oocytes that were matured in vitro were vitrified using the cryoprotectants ethylene glycol (EG) + dimethyl sulphoxide (DMSO) + sucrose and either a closed system (Rapid-i®) or an open system (Cryolock). The closed system was subsequently introduced clinically for mature oocyte cryopreservation cases and blastocyst vitrification.

RESULTS

Using in vitro matured oocytes, a similar survival was achieved with the open system of 92.4 % (73/79) and with the closed system of 89.7 % (35/39). For clinical oocyte closed vitrification, high survival rate of 90.5 % (374/413) and an implantation rate of 32.7 % (18/55) from the transfer of day 2 embryos was achieved, which is similar to fresh day 2 embryo transfers. Blastocysts have also been successfully cryopreserved using the Rapid-i closed vitrification system with 94 % of blastocysts having an estimated ≥75 % of cells intact and a similar implantation rate (31.5 %) to fresh single blastocyst transfers.

CONCLUSION

Closed vitrification can achieve high survival and similar implantation rates to fresh for both oocytes and blastocysts.